Patent Document 1 discloses a conventional solid-state imaging apparatus intended for use in X-ray imaging, for example, in the oral cavity. In this use, an X-ray incidence period for imaging is extremely short and the solid-state imaging apparatus needs to capture an X-ray incidence time to image the X-ray. Therefore, the solid-state imaging apparatus disclosed in Patent Document 1 has a trigger photodiode (hereinafter also referred to as “trigger PD”) for detection of X-ray incidence, in addition to an imaging light-receiving device including a plurality of pixel photodiodes (hereinafter also referred to as “pixel PDs”) two-dimensionally arrayed for X-ray imaging. Then this solid-state imaging apparatus monitors an electric signal output from the trigger PD to detect X-ray incidence and thereafter obtains an X-ray image, based on electric signals output from the imaging light-receiving device.
Patent Document 1: Japanese Patent Application Laid-open (translation of PCT application) No. 2002-505002